Young Folks' Library, Volume XI (of 20) eBook

But every living creature consists at first entirely
of a particle of protoplasm. Therefore every
other kind of substance which may be found in every
kind of plant or animal, must have been formed through
it, and be, in fact, a secretion from protoplasm.
Such is the rosy cheek of an apple, or of a maiden,
the luscious juice of the peach, the produce of the
castor-oil plant, the baleen that lines the whale’s
enormous jaws, as well as that softest product, the
fur of the chinchilla. Indeed, every particle
of protoplasm requires, in order that it may live,
a continuous process of exchange. It needs to
be continuously first built up by food, and then broken
down by discharging what is no longer needful for
its healthy existence. Thus the life of every
organism is a life of almost incessant change, not
only in its being as a whole, but in that of all its
protoplasmic particles also.

[Illustration: FIG. 4. AMOEBA SHOWN IN TWO
OF THE MANY IRREGULAR SHAPES IT ASSUMES. (After
Howes.)

The clear space within it is a contractile vesicle.
The dark body is the nucleus. In the right-hand
figure there is shown a particle of food, passing
through the external surface.]

Prominent among such processes is that of an interchange
of gases between the living being and its environment.
This process consists in an absorption of oxygen and
a giving-out of carbonic acid, which exchange is termed
respiration.

Lastly, protoplasm has a power of motion when appropriately
acted on. It will then contract or expand its
shape by alternate protrusions and retractions of
parts of its substance. These movements are termed
amoebiform, because they quite resemble the movements
of a small animalcule which is named amoeba. (See
Fig. 4.)

Such is the ultimate structure, and such are the fundamental
activities or functions of living organisms, as far
as they can here be described, from the lowest animalcule
and unicellular plant, up to the most complex organisms
and the body of man himself.

[Illustration]

INHABITANTS OF MY POOL

(FROM MAGIC GLASSES.)

BY ARABELLA B. BUCKLEY.

The pool lies in a deep hollow among a group of rocks
and boulders, close to the entrance of the cove, which
can only be entered at low water; it does not measure
more than two feet across, so that you can step over
it, if you take care not to slip on the masses of green
and brown seaweed growing over the rocks on its sides,
as I have done many a time when collecting specimens
for our salt-water aquarium. I find now the only
way is to lie flat down on the rock, so that my hands
and eyes are free to observe and handle, and then,
bringing my eye down to the edge of the pool, to lift
the seaweeds and let the sunlight enter into the chinks
and crannies. In this way I can catch sight of
many a small being either on the seaweed or the rocky
ledges, and even creatures transparent as glass become
visible by the thin outline gleaming in the sunlight.
Then I pluck a piece of seaweed, or chip off a fragment
of rock with a sharp-edged collecting knife, bringing
away the specimen uninjured upon it, and place it
carefully in its own separate bottle to be carried
home alive and well.